Im attempting to upgrade a 4.6.5 installation to 4.7.0...

I uninstalled all contributed modules and themes, and removed the old files and installed the new files. Once the files were in place I ran the update.php script, my first attempt I recieve the error:

user warning: Duplicate column name 'severity' query: ALTER TABLE watchdog ADD severity tinyint(3) unsigned NOT NULL default '0' in /var/www/html/drupaltestsb/includes/database.mysql.inc on line 120.

I don't even see the % status bar it just flashes to the completed page and no updates are processed. If I edit the update.php file and comment out the line that adds this query then after clicking update it just flashes to the complete screen with no updates completed.

Please Help!

Kyle